


A Letter For Arthur H. Watson

by randomhorse



Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: Alternate Universe - Harry Potter Setting, Domestic Bliss, Established Sherlock Holmes/John Watson, M/M, Parentlock, ace!sherlock, also, magic is real!, sherlock holmes has an identity crisis
Language: English
Status: Completed
Published: 2015-03-17
Updated: 2015-03-17
Packaged: 2018-03-18 08:01:12
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 8,112
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3562232
Author URL: https://archiveofourown.org/users/randomhorse/pseuds/randomhorse
Summary: <blockquote class="userstuff">
              <p>Ever since Mary's gone, John has been raising his son with Sherlock. Arthur is eleven years old, whip-smart and tall for his age. Arthur is also, as it turns out, a wizard.</p>
            </blockquote>





	A Letter For Arthur H. Watson

**Author's Note:**

> i've been sitting on this particular AU for more than a year now, trying to come up with a decent plot. this is an attempt.

The letter arrives on a Sunday. That’s the first thing that’s off about it. Then there’s the fact that it’s made from parchment and bears a scarlet red seal. And then, of course, it’s addressed neither to John Watson nor to Sherlock Holmes.

_Mr. A. H. Watson_  
The Upstairs Bedroom  
221B Baker Street  
London 

it says in neat cursive on the front. John Watson knows exactly what this means. He picks the letter from underneath the door knob and puts it safely into the inside pocket of his coat before he makes his way up the stairs, smiling to himself.

“Arthur?” he calls.

“Still asleep.” Sherlock’s quiet voice comes from the living room, where he’s rustling over something on the table. He’s up quite early for Sunday. The sun’s barely just up, sticking dusty fingers through the half-open curtains. Sherlock is still in his robe, but then he often is all day when he’s off a case and therefore not required to leave the house.

“Oh,” John says, noticing cups and a teapot and – are those plates with actual breakfast on them? – “You made breakfast.”

“Mrs Hudson did. I just set the table.”

“Rare enough,” John says, with a smile, and greets Sherlock with a kiss on the cheek. “Good morning, love.”

Sherlock gracefully accepts the gesture of affection.

“You, too.” It’s not much, but for Sherlock, it’s a lot. “Tough night?”

“It was alright, nothing out of the usual,” John says, “which reminds me.” He pulls the letter out of his inside pocket. “This came with the mail today.”

“Not the mail, clearly,” Sherlock says with a passing glance, taking the letter from John’s hand. “No mail on Sundays.”

“Not the ordinary kind of mail, anyways,” John says.

Sherlock turns the envelope in his hands, examining it carefully. “That’s genuine parchment,” Sherlock says, with a slight tone of surprise in his voice. “What is this, advertisement?”

“Not exactly,” John says, settling down in his chair across from Sherlock, beginning to enjoy the show.

Sherlock regards the address in the front with a raised eyebrow. “Why would it be addressed to your son?” he asks. “And oddly specific, too… It would have been delivered this morning”, he says, with a fleeting look out of the window, “by…” he smells the letter briefly and frowns in disbelief.

“Owl,” John says.

Sherlock’s eyes dart to John’s face. “How would you know that?”

John shrugs, a smug smile on his face. “I know things, you know.”

Sherlock rolls his eyes. “Is this a pop culture thing? Please, John. We talked about this. No one but you thinks this is funny.”

“It’s not a pop culture thing,” John says, snatching the letter from Sherlock’s hands. “And it’s not what I’d call funny. It’s pretty serious business, actually. We’re going to need to talk about this. Later. First I have to get some rest.” He gets up and stretches. “I’m going to tell Arthur that breakfast is ready, okay?” And he heads for Arthur’s room, leaving Sherlock behind, who, for once, seems to be completely at loss.

“But what is it?” Sherlock shouts after him even though John is already halfway up the stairs. “Doesn’t this concern me as well?”

“You’ll find out soon enough,” John says, and then, turning his back to knock at Arthur’s door, “Arthur? Are you awake?”

Sherlock hears a faint response, muffled by heaps of blankets and hours of sleep, but when John draws the door shut behind him, he can’t hear anything else.

  


***

 

“Arthur?” John opens the door just slightly and peeks into his son’s bedroom.

“What is it, Dad?” says a light voice, gravelly with sleep, and a tuft of blonde hair is moving underneath the heap of blankets on the bed.

“Are you awake?” John asks.

“Yeah.” Arthur kicks his blankets away and sits up, still a bit groggy, with his hair sticking up from his head. “Morning, Dad.”

“Good morning,” John says and sits down on the edge of the bed next to Arthur, careful not to destroy the matriculate arrangement of stuffed animals surrounding him. “There was a letter in the mail for you today.”

“On Sundays?” Arthur asks, frowning in disbelief. John can’t help but smile at that. The boy takes after Sherlock a lot, blood relations or not.

“It’s not an ordinary letter,” John says. “It’s going to change quite a few things for all of us. Do you want to read it?”

Arthur looks at him, eyes big and serious. Much too serious for his age, John sometimes thinks. “Is it about Mum?”

John smiles, faintly, bitterly, and shakes his head. “No. Mum’s got nothing to do with it. It’s only about you.”

“Then I want to read it.”

Arthur snuggles up, still sleep-warm and so tiny at John’s side, as John opens the envelope and unfolds the letter for both of them to read.

 

***

 

“You mean to tell me that your son –“ Sherlock says, pacing the room in agitation, his robe billowing behind him –

“ – is a wizard. Yes.” John has taken place in his armchair and follows the detective with his eyes. Arthur’s letter is in Sherlock’s hand. He looks shaken to say the least.

“But that doesn’t make any sense,” Sherlock says, with a dismissive gesture.

“Do you want to read it again?” John says, endlessly patient. When he saw the letter this morning, he knew it would take quite a bit of explaining. It’s not like the mind of Sherlock Holmes would wrap itself around that kind of thing easily.

“I don’t need to read it again,” Sherlock snaps. He stops in his movements and turns towards John. “Is this some kind of joke? Do you want me to look after him more? Is that what you want?”

“No,” John says, slightly offended by the suggestion, “I don’t want to teach you a lesson. This is happening. This is _real_ , Sherlock. I swear to God, I’m not having you on.”

“But there’s no such thing as magic.”

“Before I met you, I thought there was no such thing as a man who could tell your relationship status by glancing at your shoelaces.”

Sherlock shoots him an irritated look. “Don’t even pretend like that’s the same thing…”

“What I mean to say is,” John interrupts him, “that there’s more to reality than what meets the eye.”

“Next thing you’re going to tell me that unicorns exist,” Sherlock says.

“Actually…” John starts, but a glance at Sherlock’s face, who looks like he’s about to lose it, tells him to leave it at that. Maybe this is not the time just yet.

“So you knew all along,” Sherlock says, his voice hollow. “About that… magic… thing.”

“I didn’t know Arthur was one of them, if that helps.”

“But you knew your sister was.”

“Yeah, of course I did. She’s my sister.”

“And you didn’t feel the need to tell me.” Sherlock sounds utterly betrayed.

“Listen, Sherlock, there are rules. I couldn’t. And even if I had, which would have been madness, they would have altered your memory, and you wouldn’t have remembered any of it.”

“Altered my memory?” Sherlock looks truly horrified at the thought of that.

“There’s a spell for that, apparently.” John sighs. “There’s a thing called Statute of Wizarding Secrecy. They hide it from us, from the muggles. It’s a health and safety thing, I suppose, to keep heads like yours from exploding.”

Sherlock snorts dryly.

“You _are_ going to be okay with this, though, aren’t you?” John asks carefully. “Eventually, I mean.”

“How are _you_ so okay with this?” Sherlock asks, helplessly. He’s stopped pacing about the room, just stands there now with hanging shoulders, looking utterly lost.

John shrugs, and smiles. It’s an endearing sight, Sherlock Holmes at the edge of reason. He can’t pretend he doesn’t enjoy it a bit. “It doesn’t come as so much of a surprise for me, I guess. Actually, when he beat you at Memory at age five I should have suspected something.”

“I thought he was just smart,” Sherlock says, and there’s a trace of disappointment in his voice.

“He _is_ smart,” John says. “He really is. He takes after you a lot.”

“We’re not actually related,” Sherlock says.

“You know what I mean.”

For a second, John wonders if Sherlock actually doesn’t understand the kind of impact he’s had on Arthur’s life. There are lots of things Sherlock doesn’t understand, and John has learned to accept that, but _this_? Surely this is a thing that couldn’t get past him.

“Is _he_ okay with it?” Sherlock asks eventually, and John nods.

“He’s very okay with it. Bit shaken, I guess. But really excited. I promised him we’d buy him an owl.”

Sherlock frowns. “You do remember you’re the one who vetoed against the iguana.”

“An owl is different. They keep in touch via owl. It’s basically like setting up an e-mail account.”

“Only an email account doesn’t eat mice and shed plumage once a year.”

“As if you’d care.” John smirks. “We could call it Mycroft.” Bickering is good. Bickering means there’s no real harm done. Sherlock finally sits down in his chair, heavily, as if the pacing up and down the room has exhausted him. Actually, it’s probably the weight of what he just learned, digesting in that big brain of his, weighing him down.

“Eliminate the impossible,” Sherlock says, pondering at the words. “Apparently, nothing’s impossible.”

“You weren’t often wrong,” John says.

“But I _was_ wrong.”

“Rarely.” John smiles again, but there’s something in Sherlock’s expression that makes him wonder if this is really about his work, or something else entirely.

 

***

 

If John expected something elemental to change, now that he knows that his son is a wizard, the following days prove him utterly wrong. Actually, Arthur doesn’t change at all, goes about his day as usual, skips out of the door and down the stairs in his school uniform in the morning and leaves his bag in the corner _where it’s absolutely not supposed to be left, we talked about this, young man_ , in the afternoon. He doesn’t seem to mind much that he’s just been attested a real life equivalent of superpowers, but then, John catches himself thinking, he did grow up under the same roof as Sherlock Holmes, so people with superpowers are probably not that foreign a concept to him.

Who does change is Sherlock. And if at all possible, that worries John more than anything else.

 

***

 

“Dad?”

“Yes, Arthur?”

It’s raining in heavy silver threads, surrounding them like a veil hanging from the edge of their umbrellas. They walk a bit longer in silence, with Arthur chewing on his bottom lip, trying to find the right way to go about this.

“Sherlock is okay, isn’t he?” Arthur asks eventually, looking at John.

“What do you mean, love?” John navigates a puddle while trying to keep the bike on track. He’s pushing it along with one hand, while balancing the heavy umbrella with the other.

“I mean, well – he isn’t acting strangely, is he?” Arthur is wearing the same expression he has when arranging his stuffed animals in the precise order of his amount of affection towards them.

“Strangely? Sherlock?” John says, stifling a laugh.

“Well, _more_ strangely,” Arthur specifies.

“Why would you think that?” John asks.

“Well, he looks at me funny. He’s _staring_ at me.” Arthur kicks a pebble into the gutter. “Like, a lot. All the time, actually.”

“Is it bothering you?” John asks.

“Nah.” Arthur shrugs. “It’s just weird.”

John makes a mental note to talk to Sherlock about this. Arthur loves Sherlock a lot but John isn’t quite sure how much longer that’s going to be the case if Sherlock keeps treating him like a firecracker about to pop.

 

***

 

“I can’t see it,” Sherlock says, when they’re getting ready for bed that night. “Do you think there’s maybe been a mix-up?”

“I don’t think,” John says. “They don’t seem to go in for that sort of thing.” He sits down on the edge of the bed heavily. “Come to bed.” But Sherlock is pacing again.

“Then why don’t I see it?”

“You didn’t see I was in love with you for seven fucking years. Some things do get past you, Sherlock Holmes.”

“That was different,” Sherlock says. “First of, a sentiment thing. Then, there were mixed signals, to be fair. You did get married to a woman in the meantime. Also, you probably didn’t know yourself.”

John’s jaw tightens at the mention of Mary, still, after all these years, and Sherlock’s expression softens when he sees it.

“I’m sorry. I didn’t think.”

John forces a reassuring smile. “It’s fine.”

Sherlock seems relieved.

“Why are you so dead set on this not being true, though?” John insists.

“I don’t know,” Sherlock says. “Maybe I just want him to be like us. Normal.”

John can’t help but laugh. “Normal? Like the couple of queer adrenaline junkie boyfriends who solve crimes for kicks?”

“At least we’re not wizards.” Sherlock stops and turns towards him suddenly. “You’re not a wizard, are you?”

“No, I’m not a wizard, Sherlock,” John says, still laughing. “It doesn’t work like human genetics, it’s kind of more random than that.”

“As if you’d know the first thing about genetics.”

“I am a doctor,” John says, feigning offense. “But seriously now, Sherlock. Why are you so convinced that it’s a bad thing? Maybe that’s the greatest thing there is, being a wizard.”

Sherlock shrugs. “Maybe not.”

“Come to bed,” John says again, patting the empty spot next to him. “Get some rest.”

When Sherlock finally gets under the blanket, John puts his arm around him and pulls him in, close to him, until his upper body rests against Sherlock’s back, and his chin on Sherlock’s shoulder.

“Is this okay?,” John asks, a ritual line that falls from his lips easily every time he touches Sherlock, he doesn’t even think about it twice anymore.

“It’s fine,” Sherlock says, and John can feel Sherlock’s muscles relaxing, the tightly coiled wires inside of him finally unwinding, and the tenseness leaving, the longer they lie like that.

“I just don’t want him to be different,” Sherlock says eventually, breaking the silence.

“He’s not different,” John says. “There are tons of kids like him in that school. He’s going to make great friends. Harry made tons of friends there back in her day, and she’s, you know… Harry. He’s going to be fine. He’s special.”

“Special,” Sherlock echoes.

“Yeah,” John mumbles softly into Sherlock’s neck. “Just like you.”

From his breathing, Sherlock can tell that he’s drifted off to sleep only moments later.

“Just what I was afraid of,” Sherlock says, to no one in particular.

 

***

 

“You know I don’t actually know how to do magic yet,” Arthur says. He’s sitting in John’s chair, Sherlock in his own, watching the boy intently. Arthur has his bare feet tucked under and looks slightly worried.

“I don’t care,” Sherlock says, his fingertips touching underneath his chin.

“What do you want me to do?” Arthur asks.

“Anything at all.”

“Do you want me to set something on fire?”

Sherlock’s eyes narrow. “Could you do that?”

“No,” Arthur says, slightly annoyed. “Well, I don’t know, maybe. Where’s Dad?”

“Out.” John left early that morning, to a destination unknown, and hasn’t returned, although they’ve long passed noon and it’s beginning to grow dark outside. That’s quite out of the usual; normally Sherlock’s the one who’d do things like that. John takes care no-one has to worry about him when he’s gone. But then, what’s not out of the usual these days anymore?

“You don’t want him to know we do this, do you?” Arthur says.

Sherlock rolls his eyes. “Come on, it’s going to be fun.”

“You want me to prove it,” Arthur says, holding Sherlock’s stare steadily, not even flinching. That’s a skill that, to this day, not even John has mastered.

“So what if I do?” Sherlock asks.

“You don’t believe me.”

“I don’t believe strangers who drop parchment letters on people’s doorstep _by owl_ ,” Sherlock says, as if the owl was a particular insult to his intelligence.

“I _know_ I’m a wizard,” Arthur says stubbornly.

“How,” Sherlock asks.

“I don’t know. I just do.”

“Not enough,” Sherlock says.

“It just makes sense, you know,” Arthur says. “Like, I _know_ that it’s true, I just do. It’s like when you _know_ you’re in love with somebody. You don’t need a brain scan to prove it.”

“Not a good example,” Sherlock mutters under his breath, and then, louder, “What would you know about that?”

Arthur shrugs, and his ears go pink all of a sudden. “I don’t know. It’s just an example.”

“Anyways,” Sherlock says, slightly irritated. “Back to the point. Show me.”

“I can’t just _make_ it happen,” Arthur says. “It’s not that easy. I don’t know any tricks or spells or anything.”

“So, hypothetically,” Sherlock says. “When it happens, what actually… happens?”

“Strange things,” Arthur says. “Like, sometimes I can make puzzle pieces fit. Or sometimes, when I’m angry, I can make things burst.”

Sherlock’s eyes widen for a split second before he regains his composed, investigative attitude. “So the broken test tubes after the iguana tantrum –“

“It was an accident, I promise,” Arthur says. “It’s not like I can control it yet.”

Sherlock narrows his eyes and puts his hands back in their folded position under his chin.

“Hm,” he says, and finally reclines in his chair, waiting. “I see.”

 

***

 

“Anyways, Hogwarts is nothing like it used to be, I tell you.”

“Yeah?” John says. Half an hour at his sister’s and he’s already annoyed. He spins the tiny fragile very modern cubic designer teacup – that she uses to serve coffee, of all things – in his hand.

“Yeah, it was just a big old mess in my day. With the war going on and all.”

John scoffs. “You people were involved in the Gulf War?”

“The Wizarding War,” Harry replies. “The Return of the Dark Lord. Dark stuff. Evil stuff, I tell you. Hogwarts was mostly spared. Well, I say spared… It was hit pretty hard, but that was after I graduated. Rumour has it they ended the whole thing there, with the Potter boy and everything. But you know the tabloids. Always keen to make a story.”

John nods absentmindedly and contemplates if he should risk physical punishment for setting his cup down on Harriet’s marble table top without a coaster.

“They mostly kept the Muggles out of it, of course. Well, as much as they could. There was that whole Sirius Black thing. Well, and the dragon. I don’t actually know what they told you that was.”

“A… dragon?” John says. “You don’t mean… an _actual_ dragon?” He knows about wizards. Basic stuff. But to be fair, he has never been concerned or interested enough to dig deeper. His loss, apparently.

“Though thinking about it, they might have just _oblivate_ -d all of you. Huge thing. I was working nonstop these days. Seems kind of cynic to say it, with all the lives lost, but it was what got me here in the end.” She makes a vague gesture to the room they’re sitting in. White, spotless shiny surfaces and minimalist design. Her bracelets dingle slightly as she reaches for the teapot. “More coffee, dear?”

“I remember Sirius Black,” John says. “Had a talk about him a while back with Sherlock when he was going through old newspaper clippings. Absolutely convinced of his innocence, Sherlock was. What happened to him in the end?”

“Died,” Harry says. “Tragic story. Positively melodramatic. They did figure out he was innocent ultimately. Cleared his name. All too late, of course. Tragic. Interesting friend you got there, that Sherlock guy. He’s good.”

“Yes,” John says. “Yes, he is.”

“But that’s not why you’re here, is it.” Harry looks at him, her lipstick pink lips pursed. “You’ve not just come to catch up. Chat. You never were a big chatter. About magic, of all things.”

“No,” John says.

“It’s the boy, isn’t it?” Harry says, scrutinising him. “Mary’s boy. What’s his name again?”

“Arthur,” John says, mechanically, although he can’t believe her nerve. Any more of this and the fragile china might crack under his tightened grip.

“Arthur, yes. I remember.” She almost smiles. “So there was a letter, I presume.”

“There was,” John says, still tense.

“And…?”

“He’s going there, I guess. To Hogwarts, that is.” John swallows hard, tries to relax. There’s no good in affronting her, not now that he needs her help. “It’s all very similar to when yours arrived, way back. I remember it quite well.”

“You would,” Harry says. John wonders if she remembers the excitement she felt or his own jealousy.

“Listen, Harry, there are things I need…” he starts, but she interrupts him.

“Money?”

“No.” John closes his eyes for a second and draws a deep breath. “Advice. I don’t know anything about all of… this.” He gestures vaguely to the room, although he could barely imagine anything that looks less like magic than this.

“I have books,” Harriet says.

“I was hoping that maybe Arthur could talk to you,” John says.

“We’ve never met,” Harriet replies.

“You’re his aunt, for heaven’s sake,” John says, and checks his rising voice just in time. “You’re related.”

“Would you finally introduce me to that Sherlock friend of yours?” Harry says. “How long has it been now, John, eight, ten years? And you lived with him before as well, didn’t you. And you’ve never even thought about letting me get to know him. Or your son.”

John flinches. “And why do you think that is.” It’s not really a question, and Harry knows that.

“I don’t know why you hate me so much, John,” Harry says.

“Hate is a strong word,” John says.

“But fitting, don’t you think?”

John flinches and takes a deep breath. He curls his left hand into a fist, then flexes his fingers, a few times, until the prickling sensation subsides. “Listen, Harry. I didn’t come here to argue.” He finally sets the teacup down, forces himself to be gentle, and, to his surprise, Harry doesn’t move an inch to do anything about it.

“So, a truce,” Harry says, looking at him with bright, scrutinising eyes.

“If that’s what you want to call it.”

Harry smiles for the first time since she opened the front door to him one and a half hours ago. “A truce it is, little brother.”

 

***

 

“So,” Sherlock says. The way he picks up his mug before he proceeds (a rehearsed gesture), John can tell that he’s been through this conversation in his head countless times.

“How’s Harry?” Sherlock continues after a pause of what John is sure is a precisely calculated amount of seconds.

John doesn’t even bother to ask how he knows. He’s been living with Sherlock Holmes long enough to be used to this. It’s still baffling and surprising and fucking irritating, but John has learned to swallow those sentiments to prevent Sherlock from going on his endless deduction rants that had them missing trains, appointments and anniversaries in their first years together.

“She’s fine. Well. I say fine…”

“So she’s still horrible.”

John laughs dryly. “Yeah. Yes.”

“So why’d you meet her?” Sherlock asks, pointedly not looking at him, still trying to maintain the illusion of a casual conversation.

“Seemed like the right time,” John says.

“For what?” Sherlock asks.

John shrugs. “Making up? Shaking hands? Burying ancient feuds and move on?”

Sherlock frowns. “I still don’t know what you mean by that.”

John looks at him. “What do you mean?”

“Well, I’ve never met her,” Sherlock says. “And you never told me why you dislike her. But going by what I know now… It’s obviously a magic thing.” He shoots John a questioning glance, half to see if he’s right, half to check if he has accidentally riled him up.

John moves his head to flex his neck muscles and rolls his shoulders. He’s feeling tense lately and this conversation isn’t doing anything in his favour. “I suppose so.”

“You suppose so?”

“Yeah,” John says.

“So, is it jealousy, or…” Sherlock doesn’t look like he’s going to let this one go.

“Listen, Sherlock,” John says, carefully. “I don’t actually want to talk about this.”

“Oh,” Sherlock says, the penny finally dropping. “Oh, I’m sorry.”

Sherlock picks up his cup again, but John can see that behind his eyes that big brain of his is still whirring and working like a well-oiled clockwork. They sit in silence for a bit, Sherlock sipping his tea, John just reclining in his chair, looking around the kitchen and for once appreciating the mess he’s grown used to in the past years.

“She’s pulling some strings, you know,” John finally says. “Getting us more information about the school and wizarding… politics… I suppose. She might come round to visit herself, if Arthur thinks that talking to her is going to help him.”

“Why?” Sherlock says. “You said she’s horrible.”

“Shared experience?” John suggests. “I don’t know about you, but I for one don’t feel up to the task of explaining a whole new world to my son. One that I apparently don’t know the first thing about, no less.”

“Hm,” Sherlock says. He seems to be evaluating the information he just received, weighing the risk of annoying John further against his need for more data. John wonders why he even puts up the appearance. In the end, he’s Sherlock Holmes, and Sherlock Holmes doesn’t give a shit about how he makes anyone feel.

“Sherlock” – John starts but Sherlock interrupts him.

“Listen, John,” Sherlock says. “I’ve been in touch with the Yard about this while you were gone. They looked at me as if I was mad. Wouldn’t be the first time, mind, but this time they seemed positively concerned.”

“You’ve been doing _what_ , Sherlock?” John asks.

“We need to gather more information, John,” Sherlock says. “There’s almost nothing on the internet relating to that Hogwarts school, except some lunatics claiming that a ruin somewhere in Scotland used to be the powerhouse of the Illuminati or Freemasons and before that druids or something. Total bullshit, if you ask me.”

“Sherlock” – John tries to interrupt him, but to no avail.

“I went through public school records and there is no trace of children being taken out of elementary school to attend some sort of special education in magic or something. Really, John. I think the most obvious solution to this is that we’ve been subject to an elaborate hoax.”

“ _What_?” John spits the word out with as much incredulous disbelief as he can muster.

“You don’t actually think there is such a thing as magic. In England. In this day and age.” The last bit comes out with a bit of a chuckle that’s supposed to dull the shock, supposed to calm John down, but in fact it achieves the exact opposite.

“Sherlock, I don’t know what kind of denial you’ve slipped into in that big brain of yours, and I hate to break it to you, but _this is happening,_ ” John says. He can feel a familiar rage starting to boil in the pit of his stomach.

“John, be reasonable,” Sherlock says, wearing just the faintest trace of an incredulous smile and that’s enough to tip John over the edge.

“Jesus Christ, Sherlock. Jesus _fucking_ Christ. You are out of your mind.” He’s almost laughing. Because this. This is insane. “Is there any particular reason why you wouldn’t believe them, why you would not believe _me_? For heaven’s sake! Do you have any idea what you’re saying? Do you think I’ve been lying to you? Do you think _Arthur’s_ been lying to you?” The volume of his voice has reached emergency levels and he tries his best to check himself – to not much avail. “Do you have any idea – any idea at all – what it would do to Arthur to hear you say that? This is not one of your fucking cases, Sherlock, this is ourson we’re talking about. Our _son_.”

To anyone, Sherlock would seem entirely unfazed by this. But John can tell from the way his posture freezes and his eyes widen just the tiniest bit that he’s not.

“ _Your_ son,” Sherlock says, his voice calm and deep and pointed like a dagger.

It’s all John can do not to punch him in the face then and there. Instead he corrects his posture, involuntarily falls into parade rest, almost, and looks at Sherlock for a long moment, the silence palpable between them.

“I think it’s best you leave,” he says calmly after a long while and to his own surprise, his voice doesn’t betray him. He’s clenching his jaw, his fingers twitching at his side, and it takes all he’s got not to move when Sherlock gets up in one fluent movement, grabs his coat and scarf and, almost without a sound, vanishes down the stairs.

It’s only when he’s gone that John dares to breathe again and his first sharp intake of breath sounds too much like a sob. He clenches his fingers to a fist, still shaking, and that’s when he hears the shuffle of small feet on the carpet behind him.

He turns around to find Arthur standing in the doorframe, barefoot and tiny, eyes wide. He looks terrified.

“Hey…” John starts, instantly softer, with as comforting a voice as he can muster in his current state.

“Are you fighting?” Arthur asks quietly, keeping his distance from John who has crouched down to be on face-level with his son.

“No, Arthur..” John starts –

“Because of me?” Arthur asks.

“No!” John says, more decidedly this time. “You mustn’t think that, okay?” He pulls the boy into his arms. “Shhh,” he says, quietly, as much to calm himself down as to calm down Arthur.

“Is it because of what Sherlock did this afternoon?” Arthur mumbles into John’s sweater.

“What did Sherlock do,” John asks, softly.

“It’s okay, it was okay, really. I swear!” Arthur says hurriedly, untangling himself from John’s embrace so he can see his face. “He just didn’t want you to know because he knew you’d be mad.”

“What did he do?” John asks, again.

“We tried magic,” Arthur says. “He wanted me to show him, but I couldn’t. He said not to tell.” Arthur looks at his feet. “You’re mad at him, aren’t you?”

“Look, Arthur.” John settles down on the floor in front of his son, takes a long moment to look at him. Takes longer than he normally would, takes enough time to line out Mary’s features in his face, still familiar after all this time.

“I _am_ mad at him. He’s done some very stupid things.” He draws a long breath. “But it’s okay.” He knows he’s being kind. He’s trying to be kind to Arthur and he’s being kind to Sherlock in the extension, kinder than he deserves, probably. But that’s how family works. “We’ll be fine.”

“But he left,” Arthur says, tears welling up in his eyes, and John can tell that’s what truly terrifies him.

 _He was tiny when she left_ , John tells himself. _There’s no way he could remember._ And yet he has a boy with an army of stuffed animals required for him to fall asleep and an acute fear of being left alone. _That’s what you get growing up with a blank space for a mother_ , John thinks, bitterly. He looks at Arthur, tiny still, yet huge compared to the baby he was what feels like only months ago, and mentally renews the promise he made years ago: to never do to Arthur as was done to him. To never leave without an explanation or at least a goodbye.

“He’s coming back,” John says, and it doesn’t need any acting on his part to make it sound convincing.

 

***

 

Contrary to popular belief, Greg Lestrade does not actually live in Scotland Yard. Which is why when Sherlock shows up at the Yard past office hours and demands company and a bed to sleep in, he earns a disapproving glance from the late working detective inspector. The fact that there is a bed in his office, fully furnished with pillows at one and a rolled blanket at the other end does not particularly help his case.

“It’s for emergencies,” Lestrade explains, still disdainful.

“And do you often have emergencies?” Sherlock asks, not because he actually wants to know, but because he can see that the bed is frequently slept in, and Lestrade knows he knows, and it’s fun to rile him up.

“Unlike you, I’m actually investigating cases these days,” Lestrade replies. “Did anything come of the disappearing school children you were looking into?”

Sherlock shrugs and says nothing.

“Is everything okay?” Lestrade asks, less briskly now, and wheels around on his office chair to face Sherlock, who’s settled down on the field bed uninvited. It doesn’t need the brightest of detectives to see that something’s not right here. “How are things in 221B?”

“We’ve been fighting,” Sherlock says.

“Again?” Lestrade asks, incredulously.

“It’s not like we do this a lot,” Sherlock replies, irritated.

“You do recently,” Lestrade weighs in. “More than you used to, anyways.”

“It’s not always easy,” Sherlock says.

“Well, you could always start by being less of a self-obsessed dick,” Lestrade says, and the well-intentioned meaning of the harsh advice doesn’t escape Sherlock.

“Maybe that’d be a start,” Sherlock says, and settles down comfortably on Lestrade’s bed.

Lestrade leans back in his chair with a resigned sigh. “Can I get you anything from the vending machine?” he asks. “Coffee, tea? Packet of crisps?”

“Tea would be nice,” Sherlock says.

Lestrade gets up and accepts his fate. There’s no getting rid of Sherlock Holmes tonight.

 

***

 

At 2 a.m. there’s an incoming message on John’s phone.

I’M AT THE YARD, I’LL BE HOME IN THE MORING IF IT’S OK.

And then, 2:01:

SORRY

 

***

 

The following Saturday has a woman popping up out of thin air on the pavement in front of 221B – or at least that’s what Sherlock claims, and Sherlock, who judges his clients on basis of whether they arrive by cab, bike or foot, should be trusted on this sort of thing. Only Sherlock has been so tightly wound lately that John is not entirely sure he isn’t actually losing it. And this is not a client, this is, well. A witch, for the lack of a better word.

The witch, as it turns out, is very okay to be called exactly that. John had been worrying about the proper name, not exactly eager to use a derogatory term and accidentally insult the first member of his son’s new peer group he’s actually going to shake hands with. But “witch” is okay, as is “wizard”, he is swiftly assured – or “wizling” as the non-binary alternative – when he leads the tiny woman upstairs.

“I’ve been sent on account of the Ministry,” she explains, while John, all gentleman, helps her out of her huge, poppy red cloak. “It’s part of the new Muggle Born Inclusion Act. There have been a few revisions in the procedure since… we’ve been told we haven’t exactly been welcoming in the past…” She finishes that last sentence with an air of embarrassment, her ears the colour of the cloak John’s just hanging up in the hallway. But she recovers quickly as John leads her into the living room, where she opens her arms in a welcoming gesture, paired with a warm, wide, teeth-baring smile – “Welcome to the Wizarding Community!”

There’s a bit of an embarrassing silence in which John isn’t entirely sure if she expects him to hug her or – but when he shifts uncomfortably into her general direction she spots Sherlock in his chair in the corner, obscured, until now, by John standing in the line of sight, and all hugs are momentarily forgotten.

“Mr Holmes!” she says, instantly abandoning all over-eager cordiality and returning to, what John would call, reasonably normal human behaviour.

“Hello,” Sherlock says.

“I am _very_ pleased to meet you, Sir,” she says, eagerly stepping forward to shake his hand. “ _And_ you,” she continues equally enthusiastically and wheels back around to John, who’s still standing there, his hands hanging at his sides, just slightly taken aback by this colourful whirlwind sweeping through their flat.

“Your sister has told me so much about the two of you,” she beams. John swallows a laugh and makes a mental note to confront Harriet about _what exactly_ she’s been telling strangers about them to get them this excited.

“And now,” the witch continues ceremoniously, eyes searching the room as if she expected him to pop out behind a piece of furniture, “where is Mr. Arthur H. Watson?”

As if on cue, Arthur, not possibly able to stay unaware of the ruckus going on in the living room, comes down the stairs, hair ruffled, wearing his robe Sherlock-style, and yawning.

“What is it?” he asks, alternately looking at the three adults in the living room until his gaze fastens on the tiny witch, now wearing a knit-ensemble the colour of the sunny autumn sky outside the window.

“Hello,” he says, timidly taking a few steps forward, his eyes not leaving her face while he studies her. “Are you a witch?”

“Indeed I am,” the woman says, beaming at him. She doesn’t have to make an effort to kneel or bow down to talk to him because Arthur is tall for his age and the woman is tiny, not exceeding his height by more than a few inches. “Lovely to meet you, Arthur.”

“Likewise,” Arthur says and shakes her hand, smiling coyly, and John suddenly realizes that while Arthur didn’t make the impression to have changed much in the past week, he also didn’t smile a lot.

“So,” the witch says. “We seem to be all set. How about we put on some tea and I give you the quick basic introduction into the Wizarding Community.” Out of a bag John hasn’t noticed before (0r maybe she just conjured it out of thin air?), she produces an old-timey flip board and a – no, that’s not a sharpie. John is pretty sure that _this_ is what a wand looks like.

Arthur has taken seat at Sherlock’s feet, back leaned against his chair and his knees tucked to his chin. Sherlock might as well be a wax figurine for his lack of movement – a wax figurine that the creator for some reason wanted to look slightly panicked. John decides it’s best to just let things proceed and clean up the mess afterwards – it’s never a good idea to risk a scene with Sherlock while strangers are present – and settles down in his armchair opposite Sherlock. The encouraging glance he shoots him seems to go entirely unnoticed.

With a flip of her wand the witch dims the light and makes lines emerge on the flip board that quickly form into the words _SO YOU’VE GOT MAGIG – NOW WHAT_. John can’t help but feel impressed and Arthur’s mouth is slightly ajar. Sherlock’s face, if John’s not mistaken in the dim light, has turned an unhealthy shade of green.

“Esteemed Wizards, Wizlings, Witches and Muggles here present,” the witch begins ceremoniously, the edges of her mouth quirking upwards, “I am very proud to be your guide to the Wizarding Community today. We’ll start with the basics. If you have urgent questions, feel free to interrupt. Otherwise, I will be at your service after the lecture for as long as you may need me to answer any and all of you questions.”

 

***

 

To be entirely honest, John focuses less on the talk the witch gives than on Sherlock’s reaction to it. He can tell that Sherlock is trying to get a read on her, and fails to come up with anything to his satisfaction. John can tell by the way Sherlock flinches from time to time, as if to disturb a fly that landed on his face, and by the way his fingers grow restless on his armrests.

By the end of the talk, John only waits for the bomb to drop, but when the witch finishes with a wide grin and arms opened wide for _any and all of their questions_ , there’s a long and uncomfortable silence.

“I see that it’s all a lot to take in,” the witch says. “I could provide you with a pamphlet or two for further reading, if you’re interested in that?”

John nods, more out of civility than anything else, and gives the witch an excuse to rummage through her enormous bag, which eases the tension a little. She comes up with a few folded leaflets, sporting bright titles like _THE QUICK’N’EASY GUIDE TO MAGICAL PETS_ , _WANDLORE OR WHICH CORE TO TRUST_ , and _IT’S NOT ALL BAD – EMBRACING SLYTHERIN HISTORY IN MODERN DAY HOGWARTS_. Titles which, to John’s astonishment, seem to be _moving_.

“You can keep all of these, provided you don’t leave them lying around for muggle visitors,” the witch says brightly before she turns to Arthur. “Do you have any questions, dear?” she asks.

Arthur chews on his bottom lip for a moment, obviously trying to prioritise all the questions running through his brain.

“Where am I going to get all these things? Wands and stuff?” he asks eventually.

“Well, dear,” the witch replies, “you are in for an adventure.”

 

***

 

Later, before she’s leaving, she takes John aside in the hallway.

“It’s perfectly alright for you or Sherlock to accompany him to Diagon Alley,” she says. “It’s accustomed, even, for muggle parents to join the shopping trip. However,” she adds, and looks at him earnestly, “from Sherlock’s reaction I think it would be best to not expose him to the full extent of magic just yet.”

John nods. “I agree,” he says.

“In such cases as this I have often found it’s best if the child is accompanied by someone who’s somewhat more – well-versed in the wizarding community. Just to lend some perspective, explain things more aptly, you see?”

John nods.

“I would suggest your sister for the task, but since you’re not exactly on amiable terms…” she starts and then pauses to consider how to end the sentence gracefully. “She’s better with children than you would expect, John,” the witch says.

John can’t supress an incredulous sound.

“She may not look like it, but she does love kids. It’s too later for her to have children of her own, and she really wants to meet the boy and do right by him,” the witch adds gently. “She asked me to pass this on to you. You might consider giving her a chance.”

John takes a second to look at the tiny woman in front of him. She doesn’t seem to be much older than he is, and her short-cropped haircut and friendly eyes give her a youthful appearance.

“If you don’t mind me asking, in which capacity do you and Harriet actually… know each other?” he asks.

The witch just offers a cheeky smile. “We’ve been working together for a _really_ long time. Not much unlike you and Mr Holmes.” She winks at him. “I _know_ her, believe me.”

John laughs. And with that, it’s settled.

 

***

 

Harriet is due to arrive at 9 a.m. sharp to pick Arthur up for his shopping trip. It’s 8.30 and Sherlock looks like he’s panicking already, doing nothing for the state of John’s own nerves.

“Before you meet her,” John says, licking his lips nervously, “you should know one thing: She’s sort of psychic.”

Sherlock’s eyes go wide as all the remaining blood seems to drain from his face.

“Don’t worry, she only uses it against you if she hates you,” John says. “She doesn’t know you yet, so you still stand about a twenty percent chance of her liking you.”

As it turns out, Harry likes Sherlock. She likes him a lot. She adores him. She hangs on his lips and laughs flirtatiously at everything he says, and about ten minutes into the meeting John is sure that Sherlock is already plotting her murder.

This is not to say that she’s playing nice. John is fairly convinced that the way she likes him is not unlike the way a lioness looks at a baby zebra. Within minutes, Harriet has her claws out and John wouldn’t be surprised if he caught her licking her teeth. Sherlock, however, is not unprepared. And while for the innocent bystander he often does have elements of the baby zebra in social situations, John knows he’s ready to attack any second.

They are a magnificent pair, but not one you’d like to spend a lot of time in a closed room with.

“You’re a mind-reader,” Sherlock says.

Harriet scoffs. “That’s a bleak way to put it,” she says. “I prefer the term Legilimens.”

“Of course you would,” Sherlock says and turns to John. “Legilimens is the literal translation of _mind reader_ into Latin. Are all witches pretentious dicks or does that only apply to this particular one?”

“No need to be rude, Sherlock,” Harriet replies with a smile that’s as wide as it is fake.

“ _Indeed_ , Sherlock,” John echoes pointedly. Arthur is just coming down the stairs, and there is no need to make him feel like his newly-found aunt is anything but welcome in their family.

“Arthur!” Harriet says, and just like that, any last trace of her volatile nature has disappeared. “It’s great to meet you!” To John’s astonishment, it doesn’t even look like a put-on expression, just pure and honest interest in the boy.

Arthur beams up at her.

“Return him in one piece, if you please,” Sherlock says, his hand resting protectively on Arthur’s shoulder, guiding him towards her. “That is our son you’ve got there.”

And despite the fact that he’s just handing over his son to his sister, whom he can’t stand, and that Arthur’s slipping from his parental reach as they are standing there, and this is the first step to growing up and going separate ways, John can’t help but feel a big ball of happiness swelling in his chest, a hot, bright balloon of emotions that feel a suspicious lot like love.

“Just ring the door when you’re back. We’ll be staying up,” he says, and takes this last opportunity to brush his hand over the top of Arthur’s head to smooth out non-existent errand curls.

When they leave, Sherlock is right beside him, his body providing warmth that John feels he direly needs right now, and Sherlock, without even saying a word, curls his arm around his neck and pulls him into a long, rare hug.

 

***

 

Arthur returns from his first trip to the wizarding world absolutely _wrecked_ , and in the best sense of the word.

His face and eyes are glowing, he insists on carrying all of his boxes and bags himself, and, most precious of all, especially the long, narrow box containing his brand new wand.

“Aunt Harry taught me something!” he declares excitedly once they’re going through his heap of new belongings, his new brown owl (aptly named Strix after the Latin word for owl, although John thinks Sherlock is a tiny bit disappointed having to pass up the opportunity to christen it Mycroft) cawing lowly in its cage.

Arthur takes out his wand, a beautiful piece carved from mahogany, and swings it through the air.

“ _Lumos_ ,” he says, and a bright light breaks from the tip, throwing their shadows at the walls long and distorted until the light flickers after a few seconds and extinguishes. “She says I’ve got a talent for it,” Arthur beams, and John makes a mental note to call Harriet the next day to thank her and probably, if he can muster the energy, apologise.

“I also got you something,” Arthur says, and draws a small book from one of his bags. It’s bound in leather, and when he turns it to the front, John can read the title in big golden letters: _THE MUGGLEBORN’S GUIDE TO THE WIZARDING WORLD by HERMIONE GRANGER_.

He passes the book to Sherlock, who flips through the first few pages, a curious smile on his lips.

“Do you believe me now?” Arthur asks, climbing on Sherlock’s lap and settling there with his head tucked just under Sherlock’s chin while they flip through the pages together.

Sherlock’s fingers tangle in Arthur’s hair, and the boy bends his neck to look up at him with a grin, and John can’t help but smile because affection is so rare from Sherlock, but for once he’s got the timing exactly right.

 

***


End file.
